Transmitting apparatus for electric telegraphs.



No. 704,9!7. v V Patented .l-uly l5, I902. T. D..PENNIMAN & H. H. WIEGAND. TRANSMITTING APPARATUS- FOR ELECTRIC TELEGRAPHS.

(Application filed Feb. 18, 1902.

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witnooeo UNITED STATES PATENT OFFICE.

THOMAS D. PENNIMAN AND HENRY H. WIEGAND, OF BALTIMORE, MARY- LAND, ASSIGNORS TO THE ROWLAND TELEGRAPHIO COMPANY, OF BALTIMORE, MARYLAND, A CORPORATION OF NEW JERSEY.

TRANSMITTING APPARATUS FOR ELECTRIC .TELEGRAPHS.

$PEGIFIGATION forming part of Letters Patent NO. 704,917, dated July 15, 1902.

Application filed February 18 1902. Serial No. 94,381. (No model.)

To aZZ whom it may concern:

Be it known that we, THOMAS D. PENNIMAN andHENRYH.WInGAND,citizens of theUnited States, residing at Baltimore, in the State of Maryland, have invented certain new and useful Improvements in Transmitting Apparatus for Electric Telegraphs, (Case Q and we do hereby declare the following to be a full, clear, and exact description of the invention,

such as will enable others skilled in the art to which it appertains to make and use the same.

Our present invention relates to improvements in transmitting apparatus for electric telegraphs, and particularly to those telegraphs in which the signals are transmitted by sending over the line a succession of electrical impulses of alternate polarity and in which the characters of the code are impressed upon said current by reversing the polarity of a predetermined number of said impulses.

To this end our invention has special reference to improved apparatus for carrying out the method shown and described in United States Letters Patent of Henry A. Rowland,

No. 689,415, for improvements in electric telegraphs, granted December 24, 1901.

In the apparatus shown in the above-mentioned patent the line-circuit is derived from an alternating-current dynamo direct and is transmitted to line through a double-contact current-reversing transmitter, the polarity of the current at the dynamo-brushes remaining normal regardless of its direction through the transmitter, confining to the transmitter the entire operation of effecting the reversal of the impulses from their normal polarity. If there is any sparking, therefore, owing to these reversals, it will be confined to the transmitter-contacts, which is not to be desired. Moreover, when alternating-current dynamos are employed for furnishing the current, as upon a duplex line, the reversal of the current at one end of the line causes the dynamo at the other end to buck and in this way when applied to a synchronous system interfere with the maintenance of the true synchronism.

The object of this invention is to supply apparatus which will carry out the method described in said patent without the defects above set forth, as well as others, and this we do by derivingthe line-currentin the first instance from a source of direct current, preferably a split battery, and send alternate plus and minus impulses to line from said source of direct current by means of a pole-changer and through the forward contact and tongue of a single-contact transmitter. This transmitter we connect to the said pole-changer and said source of current in such a manner that the only function of the transmitter is to change the main line from one set of poleohanger contacts or brushes to another, so that if there is any sparking at all it will be confined to the pole-changer, where its efiect will be much less injurious than when it takes place across the contacts of the transmitter.

In order to more fully describe our said invention, reference will be had to the accompanying drawings, in which- Figure 1 represents in diagram a form of apparatus embodying our invention,and Figs.

2 and 3 are diagrammatic views of other forms of our invention.

Referring first to Fig. 1, Arepresents a rotating double pole-changer driven in any suitable manner and preferably at a constant speed. This pole-changer is provided with four lipped sections a, a, a and a upon which rest the brushes 1) c d and e f g, respectively, the brushes Z) d and e g remaining constantly in contact with their respective sections, while the central brushes 0 and f pass from one section to the next as the polechanger rotates. The brushes 6 and g are connected to the plus and minus terminals, respectively, of a source of direct current, preferably the split battery B, which is in turn grounded, as shown, or connected to the return-wire, if a complete metallic circuit be 0 employed. This source of current may, however, be a direct-current dynamo or the service-wires of any ordinary commercial directcurrent power-circuit or other source of direct current. The brush b is permanently 5 connected to the brush g, and the brush (1 with brush c, as shown. The brush f connects to the forward contact 0 of the mainline single -contact transmitter O and the brush 0 to the transmitter striker. The I00 tongue 0 of the transmitter is permanently connected to the main line L. This line rep resents any telegraph-line, whether simplex, multiplex, or duplex, since the character of the line forms no part of my invention. G represents a main-line receiving-relay adapted to operate in conjunction with the printing telegraphic apparatus described in Patents Nos. 689,753 and 689,754: to Henry A. Rowland; but any suitable form of receiving apparatus may be used. D represents any suitable sunflower device, and E one of a plurality of keys connected in the segment-circuits of said sunflower and in the circuit of said battery and transmitter-coil for operating said transmitter. We may, however, 0perate the transmitter by any suitable means, this local means being the same as in the case of the apparatus described in said Patent No. 689,415. From an inspection of the drawing Fig. 1 it will be readily seen that as the brushes 6 f and f g are alternately short-circuited by the pole-changer A an alternating current from the batteryB will pass over the line-that is, as long as the tongue of the transmitter remains against its forward contact c. \Vhen it is desired to send a signal, which is done by reversing one or more of the normal impulses and forming the code, as fully described in said Patent No. 689,415, the transmitter-magnetis energized. This is done by operating the key E, which when the sunflower-trailer arrives upon the segments connected thereto will complete the circuit of the battery F through said transmittercoils. This will cause the striker c of the transmitter to make contact with the transmitter-tongue and break connection with the contact 0, thereby shifting the current of the battery B from the brushes 6 f g to the brushes b c d and owing to the cross connection between the brushes D g and d 0 will send to line an impulse of the opposite polarity to that which would have passed to line had the transmitter not operated. As soon, however, as the trailer of the sunflower D passes to the next segment not connected to an operated key the striker of the transmitter will return to its normal position, and the current will take its usual course. The trailer of the sunflower D should rotate continuously and at such a speed as to pass over one complete segment for each impulse transmitted to line. \Vhen the trailer passes to the next segment connected to the transmitter, the operation of reversing the impulse will be repeated.

The preferred method of operating the printing-telegraph described in the patents hereinbefore referred to consists of selecting a group of impulses for each character-say eleven impulses'-and modifying two impulses in each group, the combination of the impulses thus modified representing the character. For example, the letter A would be transmitted by modifying the second and fifth impulses, the letter B by modifying the eighth and tenth, and so on. For this reason each key E when operated connects into the transmitter-coil circuit two segments. We do not, however, confine our invention to any special code of signals.

In Fig. 2 we have shown a somewhat-different arrangement of the pole-changer. In this case we do away with sections a, and a, and accomplish the same result by locating a brush 0 just one segment in advance of the brushf and connect it to the striker c of the transmitter. The rest of the connections of the pole-changer A remain the same as in the case illustrated in Fig. 1. It is quite obvious, as the brush 0 is always upon an opposite lip from the brush f, that each time the transmitter-striker operates an impulse will be sent to line of opposite sign to that which would have passed to line had the transmitter not operated. Thus in the position of the parts shown in Fig. 2 a negative impulse is passing to line through brushes f and g; but if the transmitter had operated a positive impulse would have been sent to line through brush 6, section a brush c striker c, and tongue 0 The transmitter (J in this instance is operated as in the case illustrated in Fig. 1.

In Fig. 3 is shown still another arrangement of the pole-changer. In this case the polechanger consists of a rotating ring A having four insulated segments of equal peripheral length---that is, each covering approximately a quadrant of the circle-brushes 71/, 'i, j, is, and Z disposed around one-half of the polechanger and making contact with ring A at points separated from each other by a distance equal to one-eighth of the circumference of the ring. The brushes h and Zare connected together and to one pole of the split battery, the brush 2' to the forward contact of the transmitter, brush 7a to the transmitter-striker, and the brush j to the other pole of said battery. By this arrangement eight impulses of the battery-current of alternate polarity will be sent to line for each revolution of the pole-changer. To illustrate, suppose the pole-changer starts to rotate from the position shown. During the first fortyfive degrees of its rotation the course of the current will be from line through transmittercontact a, brushes '1; and j to the negative pole of the battery, while for the next forty-five degrees the current will flow from the positive pole of the battery through brushes h and i and transmitter contact 0 to line. Then, since the brush 7a always connects to the opposite pole of the battery from that to which brush i connects, whenever the transmitter operates and connects brush into line in the place of brush '1' it is obvious that the normal impulse will be reversed. The transmitter is of course operated in this case just as described with respect to the ar rangement shown in Fig. 1.

In the following claims where we use the unmodified term pole-changer we mean to cover all possible devices which may come within this term, including not only the rotating pole-changer shown, but relays or any i I other equivalents thereof.

Having thus described our invention, what we claim, and desire to secure by Letters Patent of the United States, is

1. In transmitting apparatus for electric telegraphs, the combination with a source of direct current, of a telegraph-line, a p01echanger connected in circuit with said line and source of current, the said pole-changer having terminals arranged in sets and acting normally to deliver to line through one set, a periodic current from said source, and a mainline transmitter adapted to shift the line connection from one set of said terminals to another, whereby an impulse of opposite polarity is sent to line than would have been sent had not the transmitter acted.

2. In transmitting apparatus for electric telegraphs, the combination with a source of electric current, of a telegraph-line, a polechanger connected in circuit with said line' and source of current, thesaid pole-changer having terminals arranged in sets and acting to normally transmit to line from said source electric impulses of alternate polarity, and means adapted to shift the line connection from one set of said terminals to another whereby an impulse of opposite polarity is sent to line than would have passed had the connection not been shifted.

3. In transmitting apparatus for electric telegraphs, the combination with a source of direct current, of a telegraph-line, a rotating pole-changer connected in circuit with said line and source of current, the said pole brushes to another, whereby an impulse of opposite polarity is sent to line than would have been sent had not the transmitter acted.

4. In transmitting apparatus for electric telegraphs, the combination with a source of electric current, of a telegraph-line, a rotating pole-changer connected in circuit with said line and source of current, the said polechanger having brushes arranged in sets and acting to normally transmit to line from said source electric impulse of alternate polarity, and an electromagnetically-operated mainline transmitter adapted to shift the line connection from one set of said brushes to another whereby an impulse of opposite polar ity is sent to line than would have passed had the connection not been shifted.

5. In transmitting apparatus for electric telegraphs, the combination with a main-line transmitter, having a contact-stop, a tongue normally in engagement with said stop, a striker adapted to engage said tongue and break the contact between said stop and tongue, and means for operating said striker; of a telegraph line connected to the tongue of said transmitter, a pole-changer having two sets of terminals, one terminal of one set connected to the contact-stop of said transmitter and one of the other set connected to the striker thereof, and a source of direct current connected to the remaining brushes of both sets, the operation of said transmitter shifting the line connection from one set of pole-changer terminals to the other.

In testimony whereof we affix our signatures in presence of two Witnesses.

THOMAS D. PENNIMAN. HENRY H. WIEGAND.

Witnesses:

MURRAY Hanson, WILLIAM H. BERRY. 

